After I had upgrade to iOS 7. I cannot found this feature on my iPhone anymore. I wondered where it gone and so I do some research online. Found out that they had moved the function from your Bookmark page to the Tabs changing place. It was almost hidden. ^.^
When Apple first introduced this function, I think it was genius!
Even still now, Google Chrome and Firefox can only sync your Bookmarks through device but (Update: My friend just informed me that Chrome can also do that now.) Safari can Sync even your Tabs opened in your other devices.
The way to access this function in iOS 7 is, by pulling up at the tabs changing screen:
While on your Mac, you can see the opened tabs from your iPhone/iPad too. The way to access it is by pressing the iCloud icon located left hand side of your URL address bar:
I hope this post can help you in having an even more easier Life~